Specification 9 Cavity barriers for fire-protected timber
S9C1
Scope
2019: Spec C1.13: 1
This Specification sets out requirements for cavity barriers in fire-protected timber construction.
S9C2
Requirements
2019: Spec C1.13: 2
- At concealed cavities adjacent to junctions between fire-resisting floor/ceiling assemblies and fire-resisting walls.
- At concealed cavities adjacent to junctions between fire-resisting floor/ceiling assemblies and fire-resisting or non-combustible external walls.
- At concealed cavities adjacent to junctions between fire-resisting walls and fire-resisting or non-combustible external walls.
- Around the perimeter of door and window openings in fire-resisting construction.
- Horizontal cavity barriers — at not more than 5 m centres.
- Vertical cavity barriers — at not more than 10 m centres.
- achieve the performance specified in Table S9C2 based on the highest FRL of the elements they are mounted within or seal against; or
- consist of—
- timber with the minimum thickness specified in Table S9C2; or
- polythene-sleeved mineral wool or mineral wool slabs or strips placed under compression to achieve the minimum thickness specified in Table S9C2.
- the frame is constructed of steel or timber with the minimum thickness specified in Table S9C2 for timber; and
- the frame is tightly fitted to rigid construction and mechanically fixed in position.
System required FRL | –/60/60 or –/90/90 | –/120/120, –/180/180 or –/240/240 |
---|---|---|
Cavity barrier required FRL | –/45/45 | –/60/60 |
Timber, required minimum thickness | 45 mm | 60 mm |
Mineral wool, required minimum thickness | 45 mm | 60 mm |
Table Notes
Minimum thicknesses are to be measured in the direction of heat flow.